NTH

Amplified Does Not Mean Predictive: Reasoning Behaviors in Thinking Models

AuthorsJean de Dieu Nyandwi, Leena Mathur, Yonatan Bisk, Robert Hawkins, Graham Neubig

August 20, 2026 2 min read
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The one-line take

The paper finds that thinking models often amplify the appearance of careful reasoning more than the behaviors that truly signal correct answers.

Key results

15,282
Annotated traces

Reasoning traces analyzed across the study

15
Evaluated models

Language and vision-language models compared

6
Benchmarks

Evaluation benchmarks spanning logical, mathematical, visual, and knowledge tasks

79.6%
LLM confidence-calibration lift

Behavioral Lift associated with confidence calibration in language models

13.9%
LLM uncertainty-acknowledgment lift

Negative Behavioral Lift magnitude for uncertainty acknowledgment

40.8%
MATH-500 thinking-model recovery

Recovery rate for thinking models after detected failures

What the paper found

This study tests whether the longer, more deliberative traces produced by thinking models such as OpenAI o1, DeepSeek-R1, and Qwen3 actually contain the behaviors most predictive of correct answers. Using Behavioral Lift—defined as the accuracy difference when a behavior is present versus absent—researchers analyzed 15,282 traces from 15 language and vision-language models across 6 benchmarks, including MATH-500, MMLU-Pro, MathVista, and LogiQA2, with GPT-4o providing taxonomy annotations. Thinking models substantially amplify self-correction, hypothesis testing, and uncertainty acknowledgment, but these are not the strongest correctness signals. Confidence calibration, knowledge alignment, and self-awareness rank higher: confidence calibration has 79.6% lift for language models, while uncertainty acknowledgment has negative 13.9% lift, meaning explicit hesitation is more associated with failure than success. The main advantage of thinking models comes from recovery after intermediate errors: on MATH-500, their recovery rate reaches 40.8%, compared with 17.8% for instruct models. The pattern reverses on LogiQA2, where instruct models score 58.4% versus 54.1% for thinking models because rapid logical-form recognition is more useful than extended search. The findings argue for process objectives that reward calibrated confidence, evidence grounding, domain alignment, and effective recovery—not merely longer chains of thought or visible hesitation.

Original abstract

Which reasoning behaviors are associated with correct answers in reasoning models, and does reasoning-oriented training amplify those behaviors? This distinction is important because reasoning-oriented training can make traces look more deliberative without amplifying the behaviors most tied to model correctness. We quantify this mismatch with Behavioral Lift, a metric that measures how much correctness changes when a behavior is present versus absent in a model's reasoning trace. Across 15 models and 6 benchmarks spanning text-only and vision-language reasoning, we annotate 15,282 traces with a taxonomy whose core behaviors are defined for both LLM and VLM traces. We find evidence for an Amplification-Lift Gap, in which thinking models strongly amplify self-correction, hypothesis testing, and uncertainty acknowledgment, while the highest-lift behaviors are confidence calibration, knowledge alignment, and self-awareness. Confidence calibration is among the strongest positive signals of correctness in both modalities, yet is barely amplified; uncertainty acknowledgment is amplified by 3--7$\times$, yet is weakly or negatively associated with correctness. We find that reasoning-oriented training does not preferentially amplify the highest-Lift behaviors, motivating process-level objectives that reward calibrated and grounded reasoning rather than surface form alone.

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